SANTA CRUZ -- An international team led by UC Santa Cruz scientists have discovered four surprisingly bright and massive galaxies, among the earliest and most distant ever observed.

Using data from the Hubble and Spitzer telescopes, the team identified four particularly bright light sources, from when the universe was around 500 million years old, around 4 percent of its current age.

"As we look out in the universe, we're actually looking back in time," said Garth Illingworth, UCSC professor of astronomy and astrophysics who presented the team's findings at an American Astronomical Society meeting this week.

The galaxies discovered are so distant that their light took more than 13 billion years to reach Earth, Illingworth said.

What's unexpected is how bright and massive these galaxies are, 20 times more than any previously discovered, which means galaxies can grow faster than scientists thought, said Rychard Bouwens, a team member from the Netherlands' Leiden University.

"At the beginning of the universe it's kind of just hydrogen and helium and dark matter, a completely uniform soup," said Bouwens. "These galaxies have to grow from essentially nothing to these monstrous things in 500 million years."

One of the galaxies discovered is the second most-distant object ever observed, said Bouwens, and the rest are in the top 10.

"I think we're living in essentially a golden age of astronomy," said Bouwens. "Given the extraordinary power of these instruments, we're able to go out and make these types of discoveries." The team spent six years searching sections of the sky before making the discovery. What changed the game was public data from a powerful camera installed on the Hubble telescope three years ago, which allowed the team to make a wider survey, said Pascal Oesch, lead author of the team's paper.

"The universe at this very early time, it's very clumpy essentially," said Oesch, a former UCSC post-doctoral fellow, now at Yale. "You have to be lucky, to point in the right direction."

Oesch said the team plans to study these galaxies with other types of telescopes, to investigate properties such as gas composition, and search different portions of the sky for similar light sources.

When the universe was 500 million years old, the sky was dotted with bright blue patches, and young galaxies looked rough and irregular, unlike the spirals today, said Illingworth.

The Hubble telescope allows scientists to learn how these galaxies form and grow, he said.

"One thing that fascinates everybody is the search for origins -- origins of species, life on Earth," said Illingworth. "This is the origin for all galaxies in the universe."